The construction machines (e.g., hydraulic excavators) have been conventionally used. The construction machines mount an actuator (working unit) including e.g., an arm and a bucket on an upper structure configured to revolve.
For example, Laid-open Japan Patent Publication No. JP-A-2000-097056 (disclosed on Apr. 4, 2000) discloses an engine speed control device. In the engine speed control device, an operation lever is provided with a fuel amount increase switch. The fuel amount increase switch is actuated for increasing the engine speed by increasing the amount of fuel oil in order to solve a drawback of insufficient revolving speed of the upper structure to be cased in simultaneously operating the working unit and the upper structure.